title: Bioremoval of arsenic species from contaminated waters by sulphate-reducing bacteria.
abstract: A mixed culture of sulphate-reducing bacteria was used to study the bioremoval of arsenic species (As(III) or As(V)) from groundwater. During growth of a mixed SRB culture adapted to 0.1mg/L arsenic species through repeated sub-culturing, 1mg/L of either As(III) or As(V) was reduced to 0.3 and 0.13mg/L respectively. Sorption experiments on the precipitate produced by batch cultured sulphate-reducing bacteria (SRB-PP) indicated a removal of about 77 and 55% of As(V) and As(III) respectively under the following conditions: pH 6.9; biomass (2g/L); 24h contact time; initial arsenic concentration, 1mg/L of either species. These results were compared with synthetic iron sulphide as adsorbent. The adsorption data were fitted to Langmuir and Freundlich isotherms. Energy dispersive X-ray analysis showed the SRB-PP contained elements such as sulphur, iron, calcium and phosphorus. Biosorption studies indicated that SRB cell pellets removed about 6.6% of the As(III) and 10.5% of the As(V) from water containing an initial concentration of 1mg/L of either arsenic species after 24h contact.
authors.affiliation: Discipline of Microbiology, University of KwaZulu-Natal, Private Bag X01, 3209 Pietermaritzburg, South Africa. daniel2003g@yahoo.com
authors.forename: Daniel
authors.initials: D
authors.lastname: Teclu
authors.forename: George
authors.initials: G
authors.lastname: Tivchev
authors.forename: Mark
authors.initials: M
authors.lastname: Laing
authors.forename: Mike
authors.initials: M
authors.lastname: Wallis
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000302:isolation & purification* / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D013431:Sulfates / Q000378:metabolism*; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D013431:Sulfates; D014874:Water Pollutants, Chemical; D001151:Arsenic